Oh, you mean the one that costs $10/month extra? :\ And doesn't solve the problem of already receiving spam calls...? It seems like basically just buying a new line?
You probably got it for free because you were a T-Mobile ONE Plus customer (likely already paying a lot) [1]... otherwise it's an extra $10/month. And either way it wouldn't even solve the problem of getting too much spam at your current number...
So no, you don't have to hand out your primary number. You can create a new one there and use that for junk companies.